What is the Difference Between Carat and and Karat

In the world fine jewellery quality is king. There is really no middle ground. And when it comes to measuring gemstone and jewellery quality: the two main components that define the world of fine jewels, the two key measures are carat and karat.

They sound the same, but they refer to things which are quite different. And in application, the measures of carats and karats are key criteria with which to determine the value of your jewellery of choice. In this Education page, we will break down the two measures and how they apply in the world of precious metals and gemstones.

Is it Carat or Karat?

But before we get started the reader needs to keep in mind that the terms ‘carat’ and ‘karat’ in certain instances are used interchangeably. Meaning the conventional wisdom of carat referring to the world of gemstones and karats used in relation to precious metals (alloys specifically) does not always hold. Generally, the term carat is reserved for gemstones, like diamonds and the term karat is applied to the world of metals. However, depending on the region in question, the term carat may even apply to precious metals as well. 

In our engagement of diamond and metal quality measures in the course of our Education page we have resorted to employing these terms separately. The term carat is solely used to measure diamond or gemstone quality with respect to its weight and by extension size, and the term karat to determine metal quality with respect to the percentage of pure gold that is present in a given alloy.

OK. With that in mind let us break down each of these concepts separately, and what they mean in practice when it comes to measuring the quality of fine jewellery.

Carats as a Measure in Gemstones

The term carat in the world of gemstones refers to the weight of the gem. However, it is not a 1-for-1 substitute. One carat is the equivalent of 0.2 grams: which means a diamond which weighs 1 whole gram would equal 5 carats. So a single-carat diamond that is expertly cut will command a high price that ranges from the high thousands to close to the two grand mark. Of course, this is when we are only considering traditional colourless diamonds. 

This is telling for it shows us how tiny gemstones are in actual use, with the majority of the gemstones that are in the use in the world of gemstone jewellery, like sapphires and diamonds range 0.45 to 1.25-carat mark. Of course, there are higher-priced stones that come in larger carats, however, it is important for the reader to keep in mind the scale at which we are working when it comes to diamonds and gemstones.

In sum, carats measure the weight of the gemstones. However, is important to note that a carat of a gemstone does not denote its size. For when comparing different types of gemstones, some may appear larger despite being the same in terms of carats. For example, sapphires tend to be heavier than diamonds. So a 1 carat sapphire will appear smaller to a diamond of the same carat level. And when it comes to diamond quality carats make up the 4Cs along with the cut, clarity and colour of the gemstone. Being one of the most significant indicators of a diamond’s value, the principle that the larger the gemstone (diamond) the better the ring for the most part holds true. Gemstone jewellery buyers, like those who opt for a solitaire diamond ring stand to gain by a larger carat centre stone.

Karat as a Measure of Purity in Precious Metals

The first point to consider when it comes to metals in fine jewellery, virtually all of them that are used are in an alloy form. Meaning metals in their purest form are virtually unheard of in the making of fine jewellery. This is due to smithing reasons, where metals like gold and silver, and to a lesser extent platinum do not contain the features that make them suitable for making fine jewellery. Either they are not durable enough or malleable enough or feature other weaknesses. Hence we enter the world of metal alloying.

The usage of karats or as it is better known the system of karatage in the world of metals is a way to measure the purity of gold and other precious metals that are used in the making of fine jewels like rings, necklaces bracelets and so on. The production of metal alloys is a subject we have dealt with elsewhere. Essentially it involves combining pure precious metals like with other metals like silver, nickel, and copper in smaller amounts to change their character. This may also mean altering their dominant hue: from yellow to pink or white.

The Top Gold Karats

When it comes to the main classification of gold jewellery according to karats we have: 24K gold, 22K gold, 18K and 14K. 24 K or karat gold is pure gold. This means at the level of pure gold percentage it comes out to a solid 100 per cent. 22 K is less popular in the world of jewellery crafting, so the top gold karatage in the world of fine jewellery is the 18K variant. Which features a total pure gold percentage of around 75 per cent. 14 K gold is another top option, that is not generally a premium choice, but it is nonetheless valued for its distinct tone, with a total gold percentage of 58.3 per cent.

As the reader can see, the karatage system of measuring gold quality is a key aspect of determining the price of fine jewellery. As the price of gold jewellery like engagement rings differs with respect to the quality of the gold. However, the karatage alone is a key determinant of value: as gemstones tend to be the most significant variable. In which the carat of the stone is a significant factor.

Gemstone Carat and Gold Karat in Fine Jewellery

When it comes to the business end of any discussion concerning gemstones and metals a key consideration is how it features in my selection criteria for top jewellery. What factors should I consider in relation to gemstone carat and the karatage of gold? For starters, there is the cost. Gold that features a higher karat (i.e. 18K) commands a higher price, with 18K variants being noticeably more affordable.

But as noted, this is where the gemstone comes in. In addition to the type of gemstone in question, the carat of the stone is one of the most important variables. With a higher karat corresponding to a great price. And in the world of gemstones, we are dealing with tiny percentages.

The next key consideration when it comes to karats, which deals with precious metals like gold, is that the metal’s karatage (e.g. 18 vs 14) is an indication of the specific hue of the metal. With an 18K gold engagement ring for example being a lighter tone in gold hues like rose gold. The 14K variant, thanks to its higher alloy content is a more durable choice. Though one must have an eye on our hypoallergenic features.

A final point on gemstone carats, in the world of diamonds the 1.00 carat mark is an important number. For the moment a cut diamond hits this mark the price goes through the roof. So you are better off settling for 0.99 carats or under.